Many types of vehicles and machines include suspension struts to absorb and dampen transient forces imposed on the vehicle or machine as it travels over terrain. A typical suspension strut includes a rod and/or a piston that is slidably received within a housing (also known as a guide). Strut housings also include at least one cavity that contains a viscous fluid such as hydraulic fluid or oil. The fluid dampens movement of the rod within the housing. As the rod is retracted into the housing, fluid may exit the cavity through at least one orifice and, conversely, as the rod is extended, fluid may enter the cavity through the same or another orifice. The amount of damping provided by the strut can be adapted to the types of transient loads expected by increasing or decreasing the diameters of the orifices through which the fluid flows and/or by changing the viscosity of the fluid itself.
For large, off-road vehicles and machines, e.g., a mining truck, a typical front strut includes a hollow rod slidably received within an outer housing. A lower end of the rod may be attached to a spindle mount and the housing may be attached to the frame of the vehicle/machine. As the rod extends and retracts, harmful metal-to-metal contact may occur between the rod and the housing. To avoid this unwanted metal-to-metal contact, struts may include wear bands wrapped around the rod and disposed between the rod and the interior surface of the housing.
Strut wear bands may be subjected to two types of forces—elongation forces and compressive forces. Elongation forces are caused by axial sliding contact between the wear bands and the interior surface of the housing as the rod slides or floats within the housing. Compressive forces on the wear bands are caused by the wear bands being squeezed between the housing and the rod as the position of the rod relative to the housing shifts. These compressive forces are particularly problematic for large trucks using in mining, tar sands excavation and other operations that require the vehicle to traverse rugged terrain.
Currently, wear bands are made from polymeric materials such as a nylon, that may be cast or molded. However, it has been found that such polymeric materials do not have sufficient compressive strength properties and may fail before regular maintenance of the strut is scheduled. Because replacing the wear bands of a suspension strut is time consuming and therefore costly, improved wear bands are needed that have longer service lives. Wear bands with longer service lives would enable the wear bands to be replaced during regular maintenance of the strut and avoid the need for an additional maintenance procedure just to replace the wear bands.